This study evaluated the responses of individual daily precision (IPF) and conventional 2-phase (CON) feeding systems (FS) in terms of pig growth performance, nutrient balance, serum parameters, and meal patterns of growing pigs reared under thermoneutral (TN: 23 °C) and heat stress (high temperature [HT]: 30 °C) conditions. The animals in each treatment were assigned on the basis of equal BW to the experimental treatments (12 animals per treatment at 41.0 ± 4.87 kg of BW). The experiment lasted 55 d (phase 1 from days 0 to 27 and phase 2 from days 28 to 55). Pigs fed CON received within each phase a constant blend of diets with high and low nutrient density supplying the estimated nutrient requirements of the group, whereas the IPF pigs received daily a personalized blend providing the estimated amount of nutrients according to individual feed intake and body weight information. Body mineral content, and lean and fat masses were assessed through dual-energy X-ray absorptiometry at the beginning and end of each phase. Data were analyzed using a linear mixed-effect model, with fixed effects of the FS, temperature (AT), and the 2-way interaction between FS and AT and random effects of blocks. In relation to CON pigs, IPF pigs reduced (P < 0.05) Lys (19%), protein (16%), and P (14%) intake without impairing (P > 0.05) body composition. Nitrogen excretion was 24% lower (P < 0.05) in IPF pigs than in CON pigs; however, both groups had similar N retention efficiency thoroughly the trial. Amount of time feeding, feed intake rate, and feed intake per meal were 15% lower (P < 0.05) in pigs raised under HT than under TN conditions. During the phase 2, only amount of time feeding, feed intake rate, and feed intake per meal were decreased (P < 0.05) in pigs under HT conditions during nocturnal (2000 to 0500 h) and diurnal (0501 to 1959 h) periods. Haptoglobin levels were affected by the AT, showing an increase of 70% and 43% in HT at 28 and 55 d of the experiment, respectively. Pigs raised under HT conditions had 10% lower (P < 0.05) serum albumin concentration at day 55 than those under TN conditions. For serum urea concentrations, IPF pigs had 28% lower (P < 0.01) levels than CON pigs. Even though HT conditions considerably reduced growth performance and activated inflammatory responses in growing pigs, IPF was not able to rescue performance during HT; however, it was equally effective at improving nutrient utilization and maintaining body composition in HT and TN conditions.

This study was conducted to evaluate the effects of sequential feeding technique in two genetic lines (GL; Line A [cross having a greater proportion of Pietrain] and Line B [cross having a lower proportion of Pietrain]) of growing-finishing pigs reared under daily cyclic high ambient temperature conditions. Seventyeight castrated male pigs (22 ± 2.5 kg BW) were housed in a single group and were allocated to one of the three feeding programs: control (CON, 24 h control diet), high-fat/low-crude protein (HF/LP, 24 h high-fat/low-crude protein diet), and sequential feeding (SEQ, control diet from 1800 to 1000 h and HF/LP diet from 1001 to 1759 h). Cyclic high ambient temperature was induced by exposing the pigs to 22ºC ambient temperature from 1800 to 1000 h (time-period 22ºC, TP22) and to 30ºC from 1001 to 1759 h (TP30). The experimental period lasted 84 days and was divided into 3 growth phases, growing 1 (from day 0 to 20), growing 2 (from day 21 to 48) and finishing (from day 49 to 83). Feed intake was recorded in real time using an automatic feeder system. Pigs were weighed at the beginning and end of each experimental phase. Animal body composition was measured through dual-energy X-ray absorptiometry on days 0, 35, and 70. The ambient temperature averaged 22.3 ± 0.4ºC during TP22 and 30.2 ± 0.5ºC during TP30, characterizing the condition of daily ambient temperature variation that which pigs are usually exposed in tropical climate areas. During growing phase 1, the feeding programs had negligible effects on pig performance (P > 0.05), whereas during growing phase 2, ADG was greater in SEQ than in CON pigs (7%; P = 0.04). During the finishing phase, HF/LP pigs had greater ADFI (+ 10%) and ADG (+ 8%) than CON pigs. Lean mass and gain did not differ among feeding programs (P > 0.05). Overall, fat mass and gain were similar between SEQ and HF/LP pigs (P > 0.05), and both were greater than those of CON pigs (P < 0.05). On the basis of pig performance per phase, the supply of high-fat/low-crude protein diets (SEQ and HF/LP feeding) improved the performance of pigs under daily cyclic high ambient temperature. However, the use of these techniques resulted in fatter carcasses and in higher energy cost of gain. Finally, pigs with greater proportion of Pietrain genes had decreased growth performance in our experimental conditions.

The intestinal health of piglets depends on the balance between diet, microflora and mucosal integrity. Disruption of this balance can compromise the digestive functions, leading to diarrhoeal frame and decline in performance of piglets. However, the level and type of fibre can limit digestive disorders. Thirty newly weaned piglets were used to evaluate the levels of neutral detergent fibre (NDF) in diets regarding performance, pH, viscosity and concentration of short chain fatty acids of digestive contents, gastrointestinal transit time, morphology of the intestinal mucosa, weights of organs and occurrence of diarrhoea. NDF level had quadratic effect on weight gain and feed conversion ratio of piglets, estimating best results at the level of 10.4%. NDF level had no effect on the pH, viscosity and concentration of short chain fatty acids. NDF levels below 10.2% or above 13.5% reduced the transit time of digesta. There was quadratic effect on villus height in the duodenum and jejunum and in the crypt depth of jejunum. There was linear increase in stomach, caecum and colon weights and linear decrease in the occurrence of diarrhoea according to increasing NDF levels. It is concluded that levels below 10.2% and above 13.5% reduce the transit time of digesta, whereas 12.2% NDF level results in better mucosa structure of the small intestinal, with an increase in the weights of the stomach, caecum and colon and a reduction in the occurrence of diarrhoea with increasing NDF level in diets, resulting in better performance of weaned piglets with 10.4% of NDF.Index terms: Short chain fatty acids; pigs; transit time; viscosity. RESUMOA saúde intestinal em leitões depende do equilíbrio entre dieta, microflora e integridade da mucosa. Perturbações desse equilíbrio podem comprometer as funções digestivas, conduzindo a quadro diarreico e queda no desempenho dos leitões. Nesse sentido, o nível e tipo de fibra podem limitar as perturbações digestivas. Utilizou-se 30 leitões recém desmamados objetivando avaliar níveis de fibra em detergente neutro (FDN) nas dietas sobre o desempenho, pH, viscosidade concentração de ácidos graxos de cadeia curta dos conteúdos digestivos, tempo de trânsito gastrointestinal, do ceco, morfologia da mucosa intestinal, pesos dos órgãos e ocorrência de diarreia. Observou-se efeito quadrático do nível de FDN sobre o ganho de peso e conversão alimentar dos leitões, estimando-se melhores resultados no nível de 10,4%. Não houve efeito do nível de FDN sobre o pH, viscosidade e concentração de ácidos graxos de cadeia curta da digesta. Níveis de FDN abaixo 10.2 ou acima de 13,5% reduziu o tempo de trânsito da digesta. Houve efeito quadrático sobre a altura das vilosidades do duodeno e jejuno e na profundidade das criptas do jejuno. Houve aumento linear no peso do estômago e do ceco e cólon e redução linear na ocorrência de diarreia conforme houve aumento dos níveis de FDN. Concluiu-se que níveis abaixo de 10,2 e acima de 13,5% reduzem o tempo de trânsito da digesta, enquanto que o nível de 12,2% de NDF ...

The relative bioavailability (RBV) of a dipeptide DL-methionyl-DL-methionine (DL-Met-Met) was compared with DL-methionine (DL-Met) in growing pigs (experiment 1; N-balance study) and in weaned pigs (experiment 2; performance study). In experiment 1, 42 barrows with an initial body weight (BW) of 21.0 ± 1.37 kg were assigned to 7 dietary treatments with 6 replicate/pigs per treatment in a nitrogen (N) balance study to evaluate the RBV of DL-Met-Met to DL-Met. A basal diet (BD) was formulated to be adequate for all amino acids with the exception of Met + Cys which was 68% of the requirement [4.7 g/kg standardized ileal digestible (SID) Met + Cys; 11.5 g/kg SID Lys] for 20-25 kg pigs. Three graded levels of DL-Met (0.3, 0.6 and 0.9 g/kg) and DL-Met-Met (0.306, 0.612 and 0.919 g/kg) were supplemented to the BD to create diets 2-7. In experiment 2, a total of 189 weaned pigs (initial BW of 10.2 ± 0.98 kg) were assigned to 7 dietary treatments with 9 replicates/pens of 3 pigs per treatment. The dietary treatments consisted of a Met-deficient BD (5.3 g/kg SID Met + Cys; 13.0 g/kg SID Lys) and the same 3 graded levels of DL-Met and DL-Met-Met as in Exp. 1. In experiment 1, supplementation with DL-Met or DL-Met-Met linearly decreased (P ≤ 0.01; linear) urinary N excretion and increased (P ≤ 0.02; linear) N retained (g/day), N retention (% of intake and % of absorbed). However, there was no effect of Met sources on all N balance parameters. Based on the slope-ratio regression the RBV for DL-Met-Met compared to DL-Met was estimated 111% [95% confidence interval (CI): 63-158%] for N retained (g/d), 109% (95% CI: 57-160%) for N retention (% of intake) and 98% (95% CI: 43-154%) for N retention (% of absorbed) on an equi-molar basis. In experiment 2, the overall average daily gain (ADG) and gain:feed ratio (G:F) increased linearly (P < 0.01) by supplementation with DL-Met or DL-Met-Met. The average daily feed intake increased by supplementation with DL-Met (P = 0.02) and DL-Met-Met (P = 0.09). For ADG, the RBV for DL-Met-Met was estimated 104% (95% CI: 66-141%) on an equi-molar basis by the slope-ratio. Based on G:F, the RBV for DL-Met-Met was estimated 117% (95% CI: 61-174%) on an equi-molar basis. The results of both experiments indicate that the bioavailability DL-Met-Met is not different and at least equally bioavailable as DL-Met as a Met source for pigs.

This study aimed to investigate the effects of different net energy (NE) levels of diets with reduced crude protein (CP) that were supplemented with amino acids on feeding behavior, performance and carcass characteristics of heavy pigs (100-130 kg). Pigs were randomly allocated to experimental groups under a randomized complete block design with initial body weight as the blocking criterion. There were 5 treatments (NE levels: 2300, 2388, 2475, 2563 and 2650 Kcal NE/kg, as-fed basis) with 13 pigs per treatment, and the animal was the experimental unit. The diets were based on corn, soybean meal and wheat bran. CP levels were similar between diets and approximately 2% below the requirement (13.9%). Pigs were weighed at the beginning and end of the experiment. Electronic feeder systems automatically recorded the visits to the feeders, the timing of meals, and the amount of feed consumed per meal. Based on these recorded data, daily feed intake was calculated and feeding behavior was evaluated. At the end of the experiment, the pigs were slaughtered for carcass evaluation. Net energy levels did not affect the average daily feed intake (P > 0.05) but did influence the feeding behavior of the pigs. The pigs fed the 2388, 2475 and 2563 kcal NE/kg diets had fewer (P < 0.05) daily meals than those fed the 2300 and 2650 kcal NE/kg diets. Thus, these animals occupied the feeders for less time daily (P < 0.05) compared to those fed the 2300 and 2650 kcal NE/kg diets. The average daily NE intake increased linearly (P < 0.01) with increasing NE; however, average daily gain did not differ (P > 0.05) between treatments. There was a quadratic relationship (P < 0.01) between feed efficiency and increasing NE levels. The feed efficiency of pigs fed the 2563 kcal NE/kg diet did not differ (P > 0.05) from that of pigs in the 2388 and 2475 kcal NE/kg treatments, but was 9% higher (P < 0.05) than in the 2300 and 2650 kcal NE/kg treatments. Furthermore, loin depth and loin eye area did not change significantly (P > 0.05) when NE levels increased from 2300 to 2650 kcal NE/kg in the diets. However, a linear effect (P < 0.01) was observed for hot carcass yield and a trend toward a quadratic effect (P < 0.10) for hot carcass weight, backfat thickness and lean percentage. Among the studied levels, 2388, 2475 and 2563 kcal NE/kg produced the best results for reduced CP diets fed to heavy pigs because the pigs occupied the feeders for less time and showed higher feed efficiency.